A number of applications require the delivery of high-energy pulses. These types of applications are known generally as pulsed loads. Applications that make use of pulsed power include radar, lasers, rail guns, and pulsed thrusters for space propulsion. In order to generate the high-energy pulse necessary to drive the pulsed load, a typical power supply (e.g., a dc power source) is connected to provide charging power to a pulsed load power supply. The pulsed load power supply stores energy provided by the typical power supply in a large storage device, such as a capacitor. When a pulse of energy is required by the pulsed load, a switch connecting the capacitor to the pulsed load is closed, allowing energy stored in the capacitor to be supplied to the pulsed load.
Oftentimes, applications employing pulsed loads require the “firing” or discharge of energy through the pulsed load at a regular interval or frequency. An example of one such application is a pulsed thruster, under development for use in space propulsion systems. In order to maintain constant propulsion, the pulsed thruster is discharged repeatedly at a set frequency. The amount of energy required by the pulsed thruster results in a large amount of current being drawn from the typical power supply to the pulsed load power supply. In addition, due to the repetitious discharge of energy through the pulsed load, the current drawn from the power supply varies in time in what is known as current ripple. In some instances, current ripple caused by the pulsed load can be filtered using passive filter elements to maintain the power supply at a constant voltage. However, in applications in which the pulsed load is fired at a relatively slow frequency (e.g., 50 Hz), the passive filter elements required to filter the low frequency current ripple become large and expensive. Unfiltered current ripple has the effect of causing modulation in the typical power supply. This can result in large electrical disturbances in other components that are connected and share the same power supply. Therefore, it would be desirable to develop a pulsed load power supply circuit that is capable of providing high-energy pulses to a pulsed load without creating current ripple modulation problems in the power supply.